Severe Weather Discussion for December 6 – 12, 2010.
– Light snow is expected on Tuesday across mainly northern Oklahoma.
Light snow is again possible late Saturday. Temperatures will be in
the mid 40s Monday – Tuesday, low 50s Wednesday, upper 50s Thursday,
low 60s Friday, mid 40s Saturday-Sunday.
– I missed, on my prior forecast, that November 30th officially ends
tropical storm season.
– Severe Thunderstorms in Oklahoma: < 5%
– Storm Chase: < 5%
– Winter Precip: 5%
Sensible weather will remain at a minimum this week as only a slight
chance of snow/rain is expected on Tuesday. A weak shortwave trof
will undercut the western U.S. ridge and quickly move through the
region on northwest flow. The large closed low over the northeast
U.S. will move north-northeast through Thursday. Lack of meaningful
moisture across Oklahoma will keep precipitation
amounts low on Tuesday, along with the low amplitude of the upper wave.
Northwest flow continues for much of the week, but the cold surface
high currently over the region will shift east. This will allow a
robust warming trend to commence on Wednesday, lasting through Friday.
ECMWF/GFS are in general agreement through this time period, but
rapidly diverge by Saturday. ECMWF has another Canadian front moving
into the region on Saturday while the GFS holds it off until Sunday.
The ECMWF is my pick given general model (GFS et al) problems with
northwest flow aloft. ECMWF also amplifies a trof over the central
U.S. late Saturday and this may result in some precipitation
post-frontal. The ECMWF pulled this trick last week, so I'm not
totally biting into it. However, low POPs seem justified for late
Model trends through Friday appear reasonable, made some modifications
here and there to them. I did go lower than going forecasts on
Tuesday, as I expect cloud cover to keep temps down some. I also
followed NWS Norman on the warmup late in the week. We all tend to
agree with the ECMWF and so I went well below the GFS next Saturday
and with it on Sunday.
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